Place 120 ml of full-fat milk, 120 ml of water and 115 g of unsalted butter in a large saucepan and bring it to a gentle boil. Remove the saucepan from the heat and tip in all of the flour (160g) stirring vigorously with a wooden spoon until well combined.
Return the saucepan to the heat and keep stirring the mixture for another 2- 3 minutes until you notice a thick film forming at the bottom of the saucepan. The mixture should be very thick and smooth, with no visible lumps.
Transfer the dough into a bowl of a standing mixer, spread it into a thin layer over the sides and the bottom of the bowl with spatula and allow the mixture to cool for about 15 minutes, until it is room temperature.
Fit the mixer with paddle attachment, scrape the sides of the bowl with spatula and add two eggs into the dough. Start mixing it on a medium speed, until the eggs are well incorporated. You may have to scrape the sides of the bowl every now and then.
Add the third egg into the dough, and again mix on a medium speed until fully incorporated. Scrape the sides of the bowl as necessary. Add the egg white and lemon zest and stir again on medium speed until fully incorporated. Place the bowl with the dough in the fridge for about 10 minutes.
Transfer the dough into a piping bag fitted with large open star tip. Cut parchment paper into a small squares and brush them gently with some vegetable oil. Place the squares onto baking trays. Hold the piping bag vertically, over one of the parchment squares, start piping an even circle of dough, just making the ends to meet and connect. Repeat with the remaining dough and parchment squares. Once you have used all of the dough, place the baking trays with piped doughnuts in the fridge for an hour or in the freezer for about 30 minutes.
Heat the vegetable oil to 180 C. You can use deep fryer or a saucepan for frying your doughnuts. Gently, place the cruller in the hot oil, with the parchment paper still attached to it and facing up (although, it's fine if the parchment paper detached itself from the cruller when placing it in the hot oil). Fry the doughnuts about 2- 3 at the time for about 2-3 minutes on each side, removing the parchment paper with metal tongs after about 1 minute. They should be deep, golden brown on both sides. Remove the doughnuts from the pan using a slotted spoon and place on a large plate lined up with some paper towel. Allow the crullers to cool down completely before glazing.
For the raspberry glaze:
Mix all of the ingredients together, adding enough milk to create runny, but also thick enough glaze that will cover the doughnuts. You can run the glaze through a fine sieve to discard any raspberry seeds. Dip the doughnuts into the glaze, and enjoy!
the amount of the doughnuts will depend on how big you pipe them
keep an eye on your oil temperature at all times, make sure it doesn't exceed the 180 C mark, otherwise the crullers may burn and split
I found that chilling the doughnuts before frying them helps to prevent them from splitting when frying. You should chill them for at least an hour, but you can also chill them overnight. You can also place the doughnuts in the freezer for about 30 minutes before frying, if you are pushed for time.
crullers can also be baked instead of deep frying. Their crust will be a bit firmer, but still totally delicious! Heat the oven to 220 C (fan) and place the crullers on a baking tray, leaving 3-4 cm space between each doughnut. Place the tray with doughnuts in the hot oven and bake for 5 minutes, then reduce the heat to 160 C (fan) and bake for another 15 minutes. Turn the heat off, open the oven door slightly and allow the crullers to sit in the oven for another 10 minutes. Remove from the oven and dip them in raspberry glaze.